import os import ltspice import matplotlib.pyplot as plt import numpy as np simulations = { "longchannel": (5.0, """ .include modelcard/1um.pm .param supply = {} .param ll = 1u """), "50nm": (1.0, """ .include ./modelcard/50nm.pm .param supply = {} .param ll=50nm """), "16nmlp": (0.9, """ .include ./modelcard/PTM_LP/16nm.pm .param supply = {} .param ll=16nm """), "16nmhp": (0.7, """ .include ./modelcard/PTM_HP/16nm.pm .param supply = {} .param ll=16nm """) } moss = { "nmos": "M1 2 1 0 0 nmos W={10*ll} L= ll", "pmos": "M1 2 1 vdd vdd pmos W={10*ll} L={ll}" } script_dc = """ vdd vdd 0 {supply} Vgs 1 0 {supply} Vds 2 0 {supply} .op .dc vds 0 {supply} {supply/100} Vgs 0 {supply} {supply/12} *.step param lambda 50n 100n 10n .meas ix(1:D) at vgs='supply' .save I(vds) .end """ script_ring = """ .subckt nn d g s ww=100nm mnfet d g s gnd nmos L=ll w=ww .ends .subckt pp d g s ww=100nm mpfet d g s vdd pmos L=ll w=ww .ends .subckt inv out inn size=100n beta=2 XPP out inn vdd pp ww='size*beta/(beta+1)' XNN out inn 0 nn ww='size/(beta+1)' .ENDS inv .global gnd vdd vdd vdd 0 'supply' *Top level .ic v(n0)=0 X0 n1 n0 inv size = '10*ll' X1 n2 n1 inv size = '10*ll' X2 n3 n2 inv size = '10*ll' X3 n4 n3 inv size = '10*ll' X4 n0 n4 inv size = '10*ll' .tran 0.1p 3n """ def find_period(ident, script, model, mos, l): time = l.get_time() data = l.get_data('V(n0)') largest = max(data) smallest = min(data) diff = largest-smallest nearmax = [(i, dp) for (i, dp) in enumerate(data) if abs((largest-dp)/diff) < 0.01] nearmin = [(i, dp) for (i, dp) in enumerate(data) if abs((smallest-dp)/diff) < 0.01] group1, group2 = [], [] # Discard near-min values while nearmin[0][0] < nearmax[0][0]: nearmin.pop(0) # Group first peak while nearmax[0][0] < nearmin[0][0]: i, dp = nearmax.pop(0) group1.append((dp, time[i])) # Discard near-min values while nearmin[0][0] < nearmax[0][0]: nearmin.pop(0) # Group first peak while nearmax[0][0] < nearmin[0][0]: i, dp = nearmax.pop(0) group2.append((dp, time[i])) peak1 = max(group1)[1] * 1000000000000 peak2 = max(group2)[1] * 1000000000000 print(ident, peak2-peak1) def find_onoff(ident, script, model, mos, l): vds = l.get_data('vds') current_lo = l.get_data('I(vds)', 0) current_hi = l.get_data('I(vds)', l.case_count - 1) print(ident, current_lo[-5], current_hi[-5]) def find_gm(ident, script, model, mos, l): vds = l.get_data('vds') gms = [] for i in range(l.case_count): if i == 0: continue max_diff = max( [ abs(curr - prev) for (curr, prev) in zip(l.get_data('I(vds)', i), l.get_data('I(vds)', i-1)) ]) gms.append(max_diff/(simulations[model][0]/12)) print(ident, max(gms) * 10000) def render_current(ident, script, model, mos, l): vds = l.get_data('vds') for i in range(l.case_count): curr = l.get_data('I(vds)', i) plt.plot(vds, curr) plt.savefig(ident + "_current.png", dpi=192) plt.close() def run_sim(script, model, mos, callback): scriptname = "t_{}_{}".format(model, mos) with open(scriptname + ".cir", "w") as f: f.write(simulations[model][1].format(simulations[model][0])) if mos is not None: f.write(moss[mos]) f.write(script) if not os.path.exists(scriptname + ".raw"): sp = os.popen("wine ~/.wine/drive_c/Program\ Files/LTC/LTspiceXVII/XVIIx64.exe -b {}.cir -ascii" .format(scriptname)) sp.read() l = ltspice.Ltspice(scriptname + ".raw") l.parse() callback(scriptname, script, model, mos, l) for mos in moss.keys(): for node in simulations.keys(): run_sim(script_dc, node, mos, find_onoff) for node in simulations.keys(): run_sim(script_ring, node, None, find_period)